ROTARY MACHINE SINGLE-SUCTION INTAKE DEVICE

Abstract

The present invention provides a rotary machine intake casing which, by using a simple configuration, makes it possible to reduce asymmetry between the flow speed of air flowing in a forward direction relative to the direction of rotation of a rotating shaft of a compressor and the flow speed of air flowing in the opposite direction. Thus, a rotary machine single-suction intake device equipped with an upstream duct (121) having a suction port (121a) opening in a direction that intersects the rotational axis of the compressor, and an intake duct body section (102) for guiding air to the compressor after the air has passed into the upstream duct (121), and connected to the upstream duct (121), wherein the channel cross-sectional area on the forward direction side (A) relative to the rotational direction of the rotating shaft differs from the channel cross-sectional area on the opposite direction side (B) relative thereto, according to the flow distortion trend of the air passing through the interior of the intake duct body section (102), so as to equalize the flow speed distribution of air passing through the forward direction side (A) relative to the rotational direction of the rotating shaft and the flow speed distribution of air passing through the opposite direction side (B) relative thereto.

Claims

1. A rotary machine single-suction intake device which includes an upstream side casing having a suction port opening in a direction which intersects a rotational axis of a rotary machine and a downstream side casing which is connected to the upstream side casing and through which air passing through the inside of the upstream side casing is introduced to the rotary machine, wherein a channel cross-sectional area on a forward direction side relative to a rotational direction of a rotating shaft is different from a channel cross-sectional area on an opposite direction side relative thereto so as to equalize a flow speed distribution of air passing through the forward direction side relative to the rotational direction of the rotating shaft and a flow speed distribution of air passing through the opposite direction side, according to a flow distortion trend of the air passing through the inside of the downstream side casing.

2. The rotary machine single-suction intake device according to claim 1, wherein widths of the suction port on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.

3. The rotary machine single-suction intake device according to claim 1, wherein the downstream side casing includes a tubular channel which is formed on the rotary machine side, and wherein channel cross-sectional areas of an inlet-side opening portion of the channel on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.

4. The rotary machine single-suction intake device according to claim 1, wherein depths of the suction port on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft are different from each other.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0021] FIG. 1 is an overall view in which a gas turbine to which a rotary machine single-suction intake device according to the present invention is applied is partially cut out.

[0022] FIG. 2 is a perspective view schematically showing a rotary machine single-suction intake device according to Example 1 of the present invention.

[0023] FIG. 3 is a front view schematically showing a shape of a suction port of the rotary machine single-suction intake device according to Example 1 of the present invention.

[0024] FIGS. 4A and 4B are graphs showing a flow speed distribution in the rotary machine single-suction intake device according to Example 1 of the present invention, FIG. 4A shows a flow speed distribution in a suction port of an upstream duct, and FIG. 4B shows a flow speed distribution in an outlet portion of the upstream duct.

[0025] FIGS. 5A to 5C are views schematically showing a rotary machine single-suction intake device according to Example 2 of the present invention, FIG. 5A is a perspective view, FIG. 5B is a front view, and FIG. 5C is a sectional view of a compressor-side channel.

[0026] FIGS. 6A and 6B are view schematically showing a rotary machine single-suction intake device according to Example 3 of the present invention, FIG. 6A is a perspective view and FIG. 6B is a front view.

[0027] FIGS. 7A and 7B are view schematically showing another example of the rotary machine single-suction intake device according to Example 3 of the present invention, FIG. 7A is a perspective view and FIG. 7B is a front view.

[0028] FIGS. 8A to 8C are graphs showing a flow speed distribution in the rotary machine single-suction intake device shown in FIGS. 6A and 6B, FIG. 8A shows a flow speed distribution in a suction port of an upstream duct, FIG. 8B shows a flow speed distribution in a bent portion on a forward direction-side wall surface, and FIG. 8C shows a flow speed distribution in an outlet portion of the upstream duct.

[0029] FIGS. 9A to 9C are graphs showing a flow speed distribution in the rotary machine single-suction intake device shown in FIGS. 7A and 7B, FIG. 9A shows a flow speed distribution in a suction port of an upstream duct, FIG. 9B shows a flow speed distribution in a bent portion on an opposite direction-side wall surface, and FIG. 9C shows a flow speed distribution in an outlet portion of the upstream duct.

[0030] FIG. 10 is a perspective view schematically showing a rotary machine single-suction intake device of the related art.

[0031] FIG. 11 is a graph showing a flow speed distribution in an intake device which is applied to an axial compressor in the related art.

[0032] FIG. 12 is a graph showing a flow speed distribution in an intake device which is applied to a centrifugal compressor in the related art.

DESCRIPTION OF EMBODIMENTS

[0033] Hereinafter, an embodiment of a rotary machine single-suction intake device according to the present invention will be described.

[0034] The rotary machine single-suction intake device according to the present embodiment is a rotary machine single-suction intake device which includes an upstream side casing having a suction port opening in a direction which intersects a rotational axis of a rotary machine and a downstream side casing which is connected to the upstream side casing and through which a fluid passing through the inside of the upstream side casing is introduced to the rotary machine, and distributions in intake flow rates are biased to a forward direction side and an opposite direction side relative to a rotational direction of a rotating shaft by a single-suction intake device positioned on the upstream side of the rotary machine. Accordingly, effects of flow distortions generated by the rotation of the rotating shaft are cancelled off, and it is possible to obtain a uniform flow speed distribution in a peripheral direction in an inlet portion of the rotary machine.

[0035] A ratio of the intake flow rates between the forward direction side and the opposite direction side can be realized by changing a channel cross-sectional area of the single-suction intake device on the forward direction side and the opposite direction side relative to the rotational direction of the rotating shaft.

[0036] Here, (density)(speed)(cross-sectional area)=constant is satisfied according to a flow conservation law, and since a speed is low in a case of a suction casing, the density is approximately constant, and there is an inverse proportional relationship between the speed and the cross-sectional area.

[0037] For example, in an example of a flow speed distribution in a single-suction intake device which is applied to an axial compressor of the related art shown in FIG. 11, if it is considered that a channel is divided into channels on a forward direction side and on an opposite direction side relative to the rotational direction of the rotating shaft in flows of an inlet portion of a downstream side casing, a flow rate of the channel on the forward direction side is large (flow speed=approximately 104% of average flow speed), and the flow rate of the channel on the opposite direction side is small (flow speed=approximately 96% of average flow speed).

[0038] In order to average the flow rates, if the ratio between the channel cross-sectional area on the forward direction side and the channel cross-sectional area on the opposite direction side is set to 96:104 so as to be an inverse number of the flow speed ratio, the flow distortion is alleviated, and a vertically symmetrical flow is achieved.

[0039] Hereinafter, a specific example of the rotary machine single-suction intake device according to the present invention will be described in detail according to Examples. In addition, the present invention is not limited to the following Examples, and various modifications may be applied within a scope which does not depart from the gist of the present invention.

Example 1

[0040] A rotary machine single-suction intake device according to Example 1 of the present invention will be described with reference to FIGS. 1 to 4B.

[0041] As shown in FIG. 1, the rotary machine single-suction intake device according to the present Example is a single-suction intake duct 10 which is disposed on an upstream side of a gas turbine 1 and suctions air (fluid) in a direction approximately orthogonal to a rotational axis RL. In addition, a reference numeral 20 in FIG. 1 indicates a compressor (axial compressor), a reference numeral 30 indicates a combustor, a reference numeral 40 indicates a turbine, and a reference numeral 50 indicates a rotating shaft.

[0042] The rotary machine single-suction intake device according to the present Example adopts an upstream duct (upstream side casing) 111 shown in FIG. 2 instead of the above-described upstream duct 101 in the related art shown in FIG. 10. Other configurations are approximately similar to the configurations of the related art, and hereinafter, the configurations different from those of the intake duct shown in FIG. 10 are mainly described, and overlapping descriptions are omitted.

[0043] As shown in FIG. 2, in the upstream duct 111 of the present Example, a shape of a suction port 111a is different from that of the upstream duct 101 of the related art. Specifically, while a depth of an outlet portion 111b of the upstream duct 111 in a width direction (a direction orthogonal to the rotational axis RL and an inflow direction of air) has a constant length D, the depth of the suction port 111a is changed in the width direction.

[0044] More specifically, while a depth at an end portion on a forward direction side (a side which is positioned further forward than the center in the width direction W) A relative to the rotational direction of the rotating shaft 50 is the length D, a depth at an end portion on an opposite direction side (in the present Example, a side which is positioned further backward than the center in the width direction W) B relative to the rotational direction of the rotating shaft is a length D+d (d>0) and is longer than the depth at the end portion on the forward direction side A. In short, in the present Example, the suction port 111a has a trapezoidal shape in which the end portion on the forward direction side A is a short side and the end portion on the opposite direction side B is a long side, and the channel cross-sectional areas on the forward direction side A and the opposite direction side B are different from each other.

[0045] Here, as shown in FIG. 3, a size relation of areas (channel cross-sectional areas) of two trapezoids which are obtained by dividing the shape of the suction port 111a by the center in the width direction is set according to the flow speed distributions of the intake duct of the related art. That is, S.sub.A:S.sub.B=b:a is satisfied such that a ratio S.sub.A:S.sub.B between an area S.sub.A of the trapezoid on the forward direction side A and an area S.sub.B of the trapezoid on the opposite direction side B becomes an inverse number of the ratio a:b between the flow speed distribution on the forward direction side and the flow speed distribution on the opposite direction side shown in FIG. 11.

[0046] For example, if the ratio between the flow speed distribution on the forward direction side and the flow speed distribution on the opposite direction side shown in FIG. 11 is 104:96, a length d is set such that the ratio between the area S.sub.A of the trapezoid on the forward direction side A and the area S.sub.B of the trapezoid on the opposite direction side B becomes 96:104.

[0047] That is, the length d is represented by the following Expression (1) from S.sub.A:S.sub.B=(2D+3d/2)W/4:(2D+d/2)W/4=96:104.

d0.17D(1)

[0048] In order to set the ratio S.sub.A:S.sub.B between the area S.sub.A of the trapezoid of the forward direction side A and the area S.sub.B of the trapezoid on the opposite direction side B to 96:104, the length d may be approximately 17% of the depth D of the end portion on the forward direction side A.

[0049] According to the intake duct of the rotary machine according to the above-described present Example, since the shape of the suction port 111a is set such that the channel cross-sectional area S.sub.B on the opposite direction side B is larger than the channel cross-sectional area S.sub.A of the forward direction side A, an inflow speed of air on the opposite direction side B in the suction port 111a of the upstream duct 111 can be accelerated as shown in FIG. 4A, and with respect to the flow speed distribution of the related art shown by a two-dot chain line shown in FIG. 4B, the distribution on the inlet flow speed of the compressor 30 on the forward direction side A and the distribution on the inlet flow speed of the compressor 30 on the opposite direction side B are uniformized, and it is possible to reduce asymmetry between the flow speed of the air flowing through the forward direction side A and the flow speed of the air flowing through the opposite direction side B by a simple configuration.

[0050] Moreover, in the present Example, as shown in FIGS. 2 and 3, the example is shown in which the depth of the suction port 101a of the end portion on the opposite direction side B with respect to the end portion on the forward direction side A is enlarged toward the left side. However, the present invention is not limited to the above-described Example, the depth of the end portion on the opposite direction side B with respect to the end portion on the forward direction side A may be enlarged toward the right side or the depth of the end portion on the opposite direction side B may be enlarged toward both sides of the right and left sides as long as the channel cross-sectional area S.sub.B on the opposite direction side B is larger than the channel cross-sectional area S.sub.A on the forward direction side A, the inflow speed of the air on the opposite direction side B is accelerated, and asymmetry in the related art can be reduced.

[0051] Moreover, in the shape of the suction port 101a of the upstream duct 101, all surfaces may be flat surfaces as shown in FIGS. 2 and 3, or some surfaces may be curved surfaces.

[0052] In addition, in the present Example, the example is shown in which the length d is set such that the ratio between the area S.sub.A of the trapezoid on the forward direction side A and the area S.sub.B of the trapezoid on the opposite direction side B satisfies S.sub.A:S.sub.B=96:104. However, the ratio S.sub.A S.sub.B between the area S.sub.A of the trapezoid on the forward direction side A and the area S.sub.B of the trapezoid on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device which is applied to the present invention.

[0053] In addition, in the present Example, the example is shown in which the length d0.17D is satisfied. However, the length d may be any length as long as the length d is within a range of 0<d<0.35D

[0054] Moreover, in the present Example, the example is shown in which the present invention is applied to the axial compressor of the gas turbine. However, it is needless to say that the present invention can be also applied to a centrifugal compressor. This is similarly applied to the following Examples 2 and 3.

Example 2

[0055] A rotary machine single-suction intake device according to Example 2 of the present invention will be described with reference to FIGS. 5A to 5C.

[0056] The rotary machine single-suction intake device according to the present Example adopts an intake duct body section (downstream side casing) 112 shown in FIGS. 5A to 5C instead of the above-described intake duct body section 102 of the related art shown in FIG. 10. Other configurations are approximately similar to the configurations of the related art, and hereinafter, the configurations different from those of the intake duct shown in FIG. 10 are mainly described, and overlapping descriptions are omitted.

[0057] As shown in FIGS. 5A to 5C, in the intake duct body section 112 of the present Example, a shape of a compressor-side channel 112a is different from that of the intake duct body section 102 of the related art. Specifically, while an outer diameter side wall surface (hereinafter, referred to as a channel outer diameter-side wall surface) 112c of the compressor-side channel 112a has a shape similar to that of the related art, an inner diameter wall surface (hereinafter, referred to as a channel inner diameter-side wall surface) 112b of the compressor-side channel 112a has a shape different from that of the related art.

[0058] More specifically, while the channel inner diameter-side wall surface 112b has a shape (a perfect circular shape having a radius R.sub.A in a sectional view) similar to the shape of the related art on the forward direction side A, an upstream side of the compressor-side channel 112a on the opposite direction side B has an elliptical arc shape in a sectional view (an elliptical arc shape in which a long diameter in a sectional view is the length R.sub.A which is the same as that of the related art and a short diameter is the length R.sub.B (R.sub.B<R.sub.A)), a downstream side (inlet side of the compressor 30) of the compressor-side channel 112a has a perfect circular shape in a sectional view similarity to the related art, and the channel cross-sectional areas on the upstream side of the compressor-side channel 112a on the forward direction side A and the opposite direction side B are different from each other.

[0059] Here, a size relation between the channel cross-sectional areas on the forward direction side A and the opposite direction side B of the compressor-side channel 112a on the upstream side of the compressor-side channel 112a is set according to the flow speed distribution of the intake duct of the related art. That is, S.sub.A:S.sub.B=b:a is satisfied such that the ratio S.sub.A S.sub.B between the channel cross-sectional area S.sub.A on the forward direction side A and the channel cross-sectional area S.sub.B on the opposite direction side B becomes an inverse number of the ratio a:b between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in FIG. 11.

[0060] For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in FIG. 11 is 104:96, a length R.sub.B is set such that the ratio between the channel cross-sectional area S.sub.A on the forward direction side A and the channel cross-sectional area S.sub.B on the opposite direction side B becomes 96:104.

[0061] That is, in a case where R.sub.A is 0.70R, the length R.sub.B is represented by the following Expression (2) from S.sub.A:S.sub.B=(R.sup.2R.sub.A.sup.2):(R.sup.2R.sub.AR.sub.B)=96:104.

R.sub.B0.92R.sub.A(2)

[0062] Accordingly, in the case where R.sub.A is 0.70R, in order to set the ratio S.sub.A:S.sub.B between the channel cross-sectional area S.sub.A on the forward direction side A and the channel cross-sectional area S.sub.B on the opposite direction side B to 96:104, the short diameter R.sub.B of the channel inner diameter-side wall surface 112b on the opposite direction side B may be approximately 92% of the radius (the long diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B) R.sub.A on the forward direction side A.

[0063] According to the intake duct of the rotary machine according to the above-described present Example, in the upstream side of the compressor-side channel 112a, since the channel cross-sectional area S.sub.B on the opposite direction side B of the compressor-side channel 112a is larger than the channel cross-sectional area S.sub.A on the forward direction side A, similarly to the above-described Example 1, the inflow speed of the air on the opposite direction side B can be accelerated, and as shown in FIG. 4B, the flow speed distributions of the air in the inlet of the intake duct body section 112 on the forward direction side A and the opposite direction side B are uniformized, and it is possible to reduce asymmetry between the flow speed of the air flowing through the forward direction side A and the flow speed of the air flowing through the opposite direction side B by a simple configuration.

[0064] Moreover, in the present Example, the example is shown in which the diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B is larger than that of the related art. However, the present invention is not limited to the above-described Example, and for example, the diameter of the channel outer diameter-side wall surface 112c on the forward direction side A may be larger than that of the related art, or the diameter of the channel inner diameter-side wall surface 112b on the opposite direction side B may be larger than that of the related art and the diameter of the channel outer diameter-side wall surface 112c on the forward direction side A may be larger than that of the related art.

[0065] Moreover, the present Example may be combined with the above-described Example 1.

[0066] In addition, in the present Example, the example is shown in which the short diameter R.sub.B is set such that the ratio between the channel cross-sectional area S.sub.A on the forward direction side A and the channel cross-sectional area S.sub.B on the opposite direction side B satisfies S.sub.A:S.sub.B=96:104. However, the ratio S.sub.A:S.sub.B between the area S.sub.A of the trapezoid on the forward direction side A and the area S.sub.B of the trapezoid on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device which is applied to the present invention.

[0067] In addition, in the present Example, the example is shown in which the ratio between the long diameter R.sub.A and the short diameter R.sub.B of the channel inner diameter-side wall surface 112b on the opposite direction side B satisfies R.sub.B/R.sub.A0.92. However, the ratio between the long diameter R.sub.A and the short diameter R.sub.B may be any ratio as long as it is within a range of 0.8R.sub.B/R.sub.A<1.

Example 3

[0068] A rotary machine single-suction intake device according to Example 3 of the present invention will be described with reference to FIGS. 6A to 9C.

[0069] The rotary machine single-suction intake device according to the present Example adopts an upstream duct (upstream side casing) 121 shown in FIGS. 6A and 6B instead of the above-described upstream duct (upstream side casing) 101 of the related art shown in FIG. 10. Other configurations are approximately similar to the configurations of the related art, and hereinafter, the configurations different from those of the intake duct shown in FIG. 10 are mainly described, and overlapping descriptions are omitted.

[0070] As shown in FIGS. 6A and 6B, in the upstream duct 121 of the present Example, a shape of the upstream duct 121 on a suction port 121a side is different from that of the upstream duct 101 of the related art. Specifically, the shape of the upstream duct 121 on the forward direction side A is different from that of the related art, and the shape of the upstream duct 121 on the opposite direction side B is similar to that of the related art.

[0071] More specifically, in the suction port 121a side, in the shape on the forward direction side A of the upstream duct 121, a width W.sub.A on the side A which is positioned further forward than a center W.sub.0 (hereinafter, referred to as a center W.sub.0 in a width direction) of the outlet portion 121b in the width direction and a width W.sub.B on the side B which is positioned further backward than the center W.sub.0 in the width direction are different from each other, and the channel cross-sectional areas on the forward direction side A and the opposite direction side B are different from each other.

[0072] Here, in the present Example, the size relation between the width W.sub.A of the suction port 121a on the side A which is positioned further forward than the center W.sub.0 in the width direction and the width W.sub.B of the suction port 121a on the side B which is positioned further backward than the center W.sub.0 in the width direction is set according to the flow speed distribution of the intake duct of the related art. That is, W.sub.A:W.sub.B=b:a is satisfied such that the ratio W.sub.A:W.sub.B between the width W.sub.A of the suction port 121a on the forward direction side A and the width W.sub.B of the suction port 121a on the opposite direction side B becomes an inverse number of the ratio a:b between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in FIG. 11.

[0073] For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in FIG. 11 is 104:96, the width W.sub.A is set such that the ratio between the width W.sub.A of the suction port 121a on the forward direction side A and the width W.sub.B of the suction port 121a on the opposite direction side B becomes 96:104.

[0074] That is, the width W.sub.A is represented by the following Expression (3).

W.sub.A0.92W.sub.B(3)

[0075] Accordingly, the width W.sub.A of the suction port 121a on the forward direction side A may be approximately 92% of the width W.sub.B of the suction port 121a on the opposite direction side B.

[0076] In addition, as shown in FIGS. 7A and 7B, the shape on the forward direction side A of an upstream duct (upstream side casing) 131 may be similar to that of the related art, and the shape on the opposite direction side B of the upstream duct 131 may be different from the shape of the related art shown by a two-dot chain line. More specifically, in a suction port 131a side, the width W.sub.B on the side B which is positioned further backward than the center W.sub.0 in the width direction of the upstream duct 131 is longer than that of the related art, and the channel cross-sectional areas on the forward direction side A and the opposite direction side B are different from each other.

[0077] Even in this case, the size relation between the width W.sub.A of the suction port 131a on the side A which is positioned further forward than the center W.sub.0 in the width direction and the width W.sub.B of the suction port 131a on the side B which is positioned further backward than the center W.sub.0 in the width direction is set according to the flow speed distribution of the intake duct of the related art.

[0078] For example, if the ratio between the flow speed distribution on the forward direction side A and the flow speed distribution on the opposite direction side B shown in FIG. 11 is 104:96, the width W.sub.B is set such that the ratio between the width W.sub.A of the suction port 131a on the forward direction side A and the width W.sub.B of the suction port 131a on the opposite direction side B becomes W.sub.A:W.sub.B 96:104.

[0079] That is, the width W.sub.B is represented by the following Expression (4).

W.sub.B1.08W.sub.A(4)

[0080] Accordingly, in the example shown in FIGS. 7A and 7B, the width W.sub.B of the suction port 131a on the opposite direction side B may be approximately 108% of the width W.sub.A of the suction port 131a on the forward direction side A.

[0081] According to the intake duct of the rotary machine according to the above-described present Example, in the suction port 121a or the suction port 131a, the channel cross-sectional area S.sub.B on the opposite direction side B is larger than the channel cross-sectional area S.sub.A on the forward direction side A and the intake flow rate on the opposite direction side B is greater than the intake flow rate on the forward direction side A. Accordingly, the inflow speed of the air on the opposite direction side B can be accelerated, and as shown in FIGS. 8A and 9A, the inflow speed of the air on the opposite direction side B in the suction port 111a of the upstream duct 111 can be accelerated, the inlet flow speed distributions on the forward direction side A and the opposite direction side B of the intake duct body section 102 can be uniformized as shown in FIGS. 8C and 9C via states shown in FIGS. 8B and 9B, and it is possible to reduce asymmetry between the flow speed of the air flowing through the forward direction side A and the flow speed of the air flowing through the opposite direction side B using a simple configuration.

[0082] Moreover, in the present Example, the example is shown in which the widths are set such that the ratio between the width W.sub.A of the suction port 121a on the forward direction side A and the width W.sub.B of the suction port 121a on the opposite direction side B satisfies W.sub.A:W.sub.B=96:104. However, the ratio between the width W.sub.A of the suction port 121a on the forward direction side A and the width W.sub.B of the suction port 121a on the opposite direction side B may be appropriately set according to the flow rate distribution of the rotary machine single-suction intake device to which the present invention is applied.

[0083] For example, in the present Example, the example is shown in which the width W.sub.A0.92W.sub.B is satisfied. However, in a case where it is assumed that the maximum difference between the flow speed distribution on the forward direction side and the flow speed distribution on the opposite direction side shown in FIG. 11 is 20%, the W.sub.A may be any width as long as it is within a range of 0.66W.sub.BW.sub.A<W.sub.B.

INDUSTRIAL APPLICABILITY

[0084] The present invention is appropriately applied to a rotary machine single-suction intake device.

REFERENCE SIGNS LIST

[0085] 1: gas turbine [0086] 10: intake duct [0087] 20: compressor [0088] 30: combustor [0089] 40: gas turbine [0090] 50: rotating shaft [0091] 101, 111, 121, 131: upstream duct [0092] 101a, 111a, 121a, 131a: suction port [0093] 101b, 111b, 121b, 131b: outlet portion [0094] 102, 112: intake duct body section [0095] 102a, 112a: compressor-side channel [0096] 112b: channel inner diameter-side wall surface [0097] 112c: channel outer diameter-side wall surface